Changes in content of nitrogen and phosphorus in living and dead biomass of Calamagrostis epigejos during succession in two different old sites after coal mining
Abstract
The litter decomposition is a critical step in the mineralization of organic nutrients. The main drives of decomposition are generally water availability and litter chemical composition as indicated by its C:N:P ratio.
For studying initial stages of litter decomposition the tall grass Calamagrostis epigejos plays an important role, especially in disturbated habitats in post-mining sites. C. epigejos is very successful and can effectively suppress other plant species especially by high production of aboveground biomass that thus create a thick layer of undecomposed litter.
Also after senescence only a small part of litter falls on the soil surface and a large proportion of dead biomass remains standing for many months without contact with soil and it is limiting for microbial breakdown.The main objective of this study was to access the role of dead biomass on the turnover of nitrogen and phosphorus from the living aboveground plant biomass of C. epigejos during senescence in two different old sites in the post-mining areas. We found that a larger share of dead standing biomass were produced in the old site in contrary to the young site.
It was also observed retranslocation of nutrients from living biomass during the vegetation season especially before senescence of leaves. The aboveground plant biomass of C. epigejos was limited on the both sites more by nitrogen and that could explain a larger reabsorption of nitrogen during senescence when amount of nitrogen decreased to the lower values than other previous studies observed.
The majority of nutrients were reabsorbed before senescence because the greatest losses were subsequently after dead of biomass in August, respectively in October. And then when standing biomass turned to lying biomass, which was in contact with soil, the nutrients losses from litter was very slow.